cop 4600
DESCRIPTION
COP 4600. Objective 4 & 5. Summary of Routines. Add_cpuq() - Adds a PCB to CPU Ready Queue. Add_devq() - Adds an rb_type node to the wait queue of a device. Add_rblist() - Adds an rb_type node to the RB-list of PCB. - PowerPoint PPT PresentationTRANSCRIPT
COP 4600
Objective 4 & 5
Summary of Routines
• Add_cpuq() - Adds a PCB to CPU Ready Queue.
• Add_devq() - Adds an rb_type node to the wait queue of a device.
• Add_rblist() - Adds an rb_type node to the RB-list of PCB.
• Scheduler() - Selects the Next Process from the CPU Ready Queue to give to the CPU for execution.
• Dispatcher() - Prepares scheduled PCB’s program for execution and transfers it to CPU.
• Sio_Service() - Services interrupt to Start I/O (NON-BLOCKING function).Attempts to Start I/O on specified device if device not busy.
• Wio_Service() - Checks to see if a certain I/O operation that is waited upon is
done.(BLOCKING function).
• Eio_Service() - Services Interrupts from I/O Devices indicating the End of a previously assigned I/O operation. Attempts to Start I/O on the next node in Devices Queue.
• Start_IO() - Simulates Device providing service to nodes waiting in its Queue.
• Find_rb() - Searches PCB’s RB-List for ‘rb’.• Delete_rb() - Deallocates ‘rb’ node if found in
PCB’s RB- List.• Purge_rb() - Purges all RB’s with Status as ‘D’ –
Done.• Load_Map() - Initializes MEMMAP h/w with
Dispatched Programs Segment Table
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
LOGON(U001)LOGON(U003)LOGON(U002)LOGON(U004)
Script.dat
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
LOGON(U001)LOGON(U003)LOGON(U002)LOGON(U004)
wait
QUEUE
PCB1
PCB 1
Editor.dat
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
LOGON(U003)LOGON(U002)SIO 23LOGON(U004)
wait
QUEUE
PCB1PCB 1
Editor.dat
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
LOGON(U002)SIO 23LOGON(U004)
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 23LOGON(U004)
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
wait
QUEUE
PCB2
PCB 2
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
LOGON(U004)SIO 32EIO
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
LOGON(U004)SIO 32EIO
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 32WIO
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
wait
QUEUE
PCB4
PCB 4
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
WIO
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
wait
QUEUE
PCB4
PCB 4
PCB1300
DISK 300
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
WIO 0EIOEIO
wait
QUEUE
PCB1PCB 1
Editor.dat
wait
QUEUE
PCB3
PCB 3
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
wait
QUEUE
PCB4
PCB 4
PCB1300
DISK 300
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 27EIOEIO
wait
QUEUE
PCB1PCB3
wait
QUEUE
PCB3
PCB 2
wait
QUEUE
PCB2
PCB 4
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
Script.dat
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 15EIOEIO
wait
QUEUE
PCB1PCB3
wait
QUEUE
PCB3
PCB 2
wait
QUEUE
PCB2
PCB 4
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
PCB33000
DISK 3000
Printer.dat
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
ENDEIOEIO
wait
QUEUE
PCB1PCB3
wait
QUEUE
PCB3
PCB 2
wait
QUEUE
PCB2
PCB 4
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
Printer.dat
PCB33000
DISK 3000 PRNT 100PCB 3100
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 10EIOEIO
wait
QUEUE
PCB1
wait
QUEUE
PCB3
PCB 4
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
Editor.dat
PCB33000
DISK 3000 PRNT 100PCB 3100
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
WIOEIOEIO
wait
QUEUE
PCB1
wait
QUEUE
PCB3
PCB 4
wait
QUEUE
PCB2
PCB 2
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
Editor.dat
PCB33000
DISK 3000 PRNT 100PCB 3100
PCB21000
DISK 1000
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 18EIOEIO
wait
QUEUE
PCB1
wait
QUEUE
PCB3
PCB 4
wait
QUEUE
PCB2
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
printer.dat
PCB33000
DISK 3000 PRNT 100PCB 3100
PCB21000
DISK 1000
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
WIOEIOEIO
wait
QUEUE
PCB1
wait
QUEUE
PCB3
PCB 4
wait
QUEUE
PCB2
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
printer.dat
PCB33000
DISK 3000 PRNT 100PCB 3100
PCB21000
DISK 1000
DISK 1000
PCB41000
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
EIOEIO
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
printer.dat
PCB33000
DISK 3000 PRNT 100PCB 3100
PCB21000
DISK 1000 DISK 1000
PCB41000
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
EIO(PRNT PCB1)EIO(DISK PCB1)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB1100
PRNT 100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
PCB33000
DISK 3000 PRNT 100PCB 3100
PCB21000
DISK 1000 DISK 1000
PCB41000
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
EIO(DISK PCB1)EIO(PRNT PCB3)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB3100
wait
QUEUE
PCB4PCB1300
DISK 300
DISK 300
PCB33000
DISK 3000 PRNT 100
PCB21000
DISK 1000 DISK 1000
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
EIO(PRNT PCB3)EIO(DISK PCB3)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB3100
wait
QUEUE
PCB4PCB 33000
PCB21000
DISK 3000 PRNT 100
DISK 1000 DISK 1000
PCB 1
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
SIO 15EIO(PRNT PCB3)EIO(DISK PCB3)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB3100
wait
QUEUE
PCB4PCB 33000
PCB21000
DISK 3000 PRNT 100
DISK 1000 DISK 1000
PCB 1
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
ENDEIO(PRNT PCB3)EIO(DISK PCB3)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB3100
PRNT 150
wait
QUEUE
PCB4PCB 33000
PCB21000
DISK 3000 PRNT 100
DISK 1000 DISK 1000
PCB 1
PCB 1150
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
ENDEIO(PRNT PCB3)EIO(DISK PCB3)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB3100
wait
QUEUE
PCB4PCB 33000
PCB21000
DISK 3000 PRNT 100
DISK 1000 DISK 1000
PCB 1
PCB 1150
CPU
PRNT
DISK
actvpcb
QUEUE
currb
QUEUE
currb
QUEUE
EIO(PRNT PCB3)EIO(DISK PCB3)
wait
QUEUE
PCB1
wait
QUEUE
PCB3
wait
QUEUE
PCB2
PCB3100
PRNT 150
wait
QUEUE
PCB4PCB 33000
PCB21000
DISK 3000 PRNT 100
DISK 1000 DISK 1000
PCB 1150
Interrupt() Interrupt_Handler() Schedular() Dispatcher()
Logon() Sio_Service() Wio_Service() Eio_Service() End_Service()(Obj 3)
(Obj 3)Additional Statements used
-Initialize ‘rb’-Add_devq()-Add_rblist()-StartIO()
-Find_rb()-If(‘P’ or ‘A’)BLOCK-elseDelete_rb()
-Mark RBStatus as ‘D’-StartIO()-Cases forpcb->status
-Purge_rb()-Next_pgm()
Interrupt() Interrupt_Handler() Schedular() Dispatcher()
-LoadMap()-XPGM()
Add_cpuq(struct pcb_type *pcb) Create a pcb_list* node and set pcb to the pcb_type pointer in
the node If the wait queue in CPU is empty, add
the node to head of the wait queue. Update the tail in CPU
Otherwise, add the node to the end of the wait queue in the CPU. Update the tail.
• Add_devq(int dev, struct rb_type *rb) Create a rb_list* node and set rb to the rb_type pointer in the
node Record the time when the rb is queued If the device is empty, add the node to
head of the wait queue in device. Update the tail in device
Otherwise, add the node to the end of the wait queue in the device. Update the tail.
• Add_rblist(struct pcb_type *pcb, struct rb_type *rb) Create a rb_list* node and set rb to the rb_type pointer in the
node If the rb_list queue is empty in pcb, add
the node to head of the rb_list queue in pcb. Update the tail in pcb
Otherwise, add the node to the end of the rb_list queue in the pcb. Update the tail.
Struct pcb_type* scheduler() If the ready queue in CPU is empty,
return Update the number of processes served
by the CPU FCFS:
Grab the first node in the list Record when the process became ACTIVE Calculate time process was READY and
increment CPU qwait time
Dispatcher() Prepares the scheduled program for
execution and then transfers control to it LoadMap ( CPU.avtvpcb->segtable,
CPU.actvpcb->segtab_len)
XPGM(&CPU.actvpcb->cpu_save);
rb_type* Alloc_rb() Allocates an I/O request block (rb) Sets rb->status to “Pending” Sets rb->pcb to Termtable[AGENT –1] The device instruction must be found in
memory using only the current pcb with the pcb's saved program counter incremented passed the point needed.
We subtract 1 from the offset when calculating the device instruction since we increment offset by 2 in Cpu()
When calculating the request ID for the rb, one is subtracted from the offset since 2 was added to PC in Cpu()
EG: SIO 35,PRNT 200, WIO 24
Alloc_rb ( ) (contd..) Set rb->bytes Set rb-> reqid to logical address of Device
instruction rb-> reqid.segment = rb->pcb->cpu_save.pc.segment ; rb-> reqid.offset = rb->pcb->cpu_save.pc.offset – 1;
Sio_service() (Non Blocking function) Allocate & initialize new rb Add_devq(); Add_rblist(); Attempt to initiate an operation on the
requested device – StartIO(); Set CPU_SW = 1 and SCHED_SW = 0;
Wio_Service(void) (Blocking Function) Retrieve pcb from Term_table Locate REQ instruction to retrieve address
field. Call Find_rb() to to get status of IO operation
waited upon. If status is ‘P’ or ‘A’, BLOCK pcb. Set CPU_SW = SCHED_SW = 1 Calculate ACTIVE time for process and Busy
time for CPU Record the time the process what blocked and
return. Else process can continue running.
Call Delete_rb() to deallocate the IORB. Set CPU_SW = 1 , SCHED_SW = 0;
Eio_Service(void) Self explanatory See the objective 4
Start_IO(int dev)
[ Attempts to start an operation on a device (dev) ]
If Device is busy : devtable[dev].currb != NULL - return .
If Device Queue is empty - return. Remove the next rb from the device queue and store it
in ‘currb’ Update Total Wait time for the device while in Queue Calculate the time (eiotime) at which the operation will
terminate depending on Device Speed Update Device’s Busy Time Create future time event for IO operation Add_event(&eiotime, EIO , dev+TRMSIZE + 1) Update number of IO requests served for the device.
• Find_rb()[ Searches RB list of PCB to locate an RB ]
• Delete_rb()
[ Deletes and deallocates an ‘rb’ from the PCB RB list]
• Purge_rb()
[Purges all RB’s with COMPLETE Status ]• LoadMap()
[ Initialises the MEMMAP hardware to dispatched programs segment table ]
Objective 5 Calc_stats(void)[ The Function computes all the simulation statistics and
stores them in the appropriate variables and data structures for display. This function is called by Wrapup() ]
for i = 0 to TRMSIZE // I.e for each PCB { Total Processing time - TOTLOGON Total Job blocked time - TOTBLKED Total Job Wait time - TOTWAIT Total Job Execution Time – TOTRUN Efficiency for each process – temp = total blocked time + total Run time termtable[i]->effciency = 100.0 * Divd_time( &temp,
&termtable[i]->tlogon ); }
for i= 0 to DEVSIZE{[ Calculate Response time for all devices ]• temp = Busy time + Qwait time• Ave_time(,&temp ,&devtable[i].num_served ,
&devtable[i].response);[ Calculate idle time ]• devtable[i].idle.seconds = CLOCK.seconds• devtable[i].idle.nanosec = CLOCK.nanosecDiff_time( &devtable[i].busy, &devtable[i].idle )[ Utilization ]Devtable[i].utilize = 100.0 * Divd_time(&devtable[i].busy,&CLOCK)}
• Average user execution time using TOTRUN and TRMSIZE• Average user logon time using TOTLOGON and TRMSIZE• Average Blocked Time using TOTBLKED and TRMSIZE• Average User wait Time using TOTWAIT and TRMSIZE
• Response Time for CPU temp = busy + qwait Ave_time(,&temp,CPU.served,&CPU.response)• Idle time for CPU CPU.idle.seconds = CLOCK.seconds CPU.idle.seconds = CLOCK.seconds Diff_time(&CPU.busy, &CPU.idle)
• Total Utilization for CPU CPU.utilize = 100.0 * Divd_time (&CPU.busy, &CLOCK)